Reality Factory

There are free small games like these

http://www.playunitygames.com/search/label/defense

you can download and play instantly in the web page widow (or even fullscreen) and use a plugin for running the game in there.

Could rf be played like this in a web browser -if i could find someone to host it using a generic plugin or something-
or the plugin has to do with the rf game engine specifically and would require modification of rf core?

Browser applications... that isn't what RF is as far as I know. If you want to make browser games than you should Java Programming.

You can use Unity3D as well.

I learned something new today!